Embodiments of the present invention relate to test instruments, and more particularly to portable test instruments for measuring communications signals.
Portable test instruments, such as those used in communications testing to test wireless network base stations, and transmitters, for voice, data or other communications, rely on a timing reference for certain types of measurements, or to correlate measurements in time. An available timing source that has been used for outdoor testing is a global positioning system (GPS) signal which is provided by a GPS satellite. A GPS signal is not typically available in an indoor environment. However, there is still a desire to provide testing of wireless communications systems within indoor environments.